1. Field of the Invention
The present invention relates to a power amplifying circuit capable of having improved operational efficiency and manufacturing yield and reducing manufacturing costs by including impedance matching circuits distributed and disposed in an amplifying circuit unit amplifying a plurality of wireless signals having different frequency bands and a filter selectively transmitting or receiving at least one of the plurality of wireless signals, and a front end module including the same.
2. Description of the Related Art
As mobile apparatuses such as smartphones, tablet personal computers (PCs), and the like, transmitting and receiving data using wireless communications have been rapidly popularized, research into a dual band communications module providing wireless communications based on wireless signals in different frequency bands has been actively undertaken. Therefore, a large number of recently released mobile apparatuses such as smartphones, tablet PCs, and the like, are provided with a function able to perform communications using a plurality of wireless signals having different frequency bands. Therefore, a dual band access point (AP) product setting a wireless local area network (LAN) using wireless signals having different frequency bands has also been released.
A general front end module performing communications based on wireless signals having different frequency bands includes a driving circuit controlling transmission and reception of the wireless signals, an amplifying circuit amplifying the wireless signals to be transmitted, and a filter filtering the transmitted and received wireless signals. In this case, impedance matching between an output terminal of the amplifying circuit outputting the wireless signal and an input terminal of the filter transferring the wireless signal to an antenna or receiving the wireless signal from the antenna should be appropriately performed in order to prevent wireless communications efficiency from being deteriorated.
An existing front end module includes a circuit capable of varying impedance from 5 ohms to 50 ohms and an output matching circuit in order to perform the impedance matching between the output terminal of the amplifying circuit and the input terminal of the filter. However, in the case of configuring the circuit as described above, the overall manufacturing costs of the front end module may be increased, and a high degree of resistance loss may occur due to an inductor included in the matching circuit.
In the related art documents below, Patent Document 1, relating to a front end module for local area wireless communications, discloses a circuit including a power amplifying device and a filter. Patent Document 2, relating to a multi-stage amplifier, includes an amplifying device amplifying power and a multi-stage matching circuit as its components. However, neither Patent Document 1 nor Patent Document 2 discloses a configuration of distributing and implementing impedance matching circuits in an amplifying circuit and a filter and setting impedance matching ranges of the impedance matching circuits included in the amplifying circuit and the filter to be continuous.